Pressure relief and indicator device

ABSTRACT

A device which senses a differential pressure across a system having a high pressure side and a low pressure side and which at a predetermined pressure of pressure difference functions to bypass the flow from the high pressure to the low pressure side. There is pressure responsive means and indicator means, the indicator means functioning upon the pressure sensitive means moving in response to an increase in differential pressure.

nitell States Patent ammer et al.

[ 51 ar.2,l972

[54] PRESSURE RELIEF AND INDICATOR DEVICE [72] Inventors: Kurt F. Hammer; Wilbur A. Meyer, both of Camarilio, Calif.

[73] Assignee: Puroiator, Inc., Rahway, NJ.

[22] Filed: Jan. 13, 1970 [21] Appl. No.: 2,493

[52] 0.8. Ci ..l37/469,137/556.3, 137/557 [51] Int. Cl [58] Field 01 Search ..l37/469, 472, 473, 474, 475,

[56] References Cited UNITED STATES PATENTS 2,221,724 11/1940 Safford ..l37/469 2,644,480 7/1953 Earle ..l37/469 3,042,061 7/1962 Dobrikin 137/557 X 3,409,037 11/1968 Nelson ..137/469 X FOREIGN PATENTS OR APPLICATIONS 649,014 1/1951 Great Britain ..l37/47l Primary Examiner-Harold W. Weakley Att0rney--Whann & McManigal [5 7] ABSTRACT A device which senses a differential pressure across a system having a high pressure side and a low pressure side and which at a predetermined pressure of pressure difference functions to bypass the flow from the high pressure to the low pressure side. There is pressure responsive means and indicator means, the indicator means functioning upon the pressure sensitive means moving in response to an increase in differential pressure.

4 Claims, 6 Drawing Figures BACKGROUND OF INVENTION Our invention is useful in fluid systems or hydraulic systems or lubrication circulating systems which ordinarily employ a filter for filtering the fluid. When a filter starts to clog its passage area is gradually reduced and a back pressure is gradually built up on the high pressure side of the system. when this back pressure produces a predetermined differential in pressure between the high pressure side and the low pressure side the filter must be replaced. Pressure increases in the high pressure side of such system occur if pressure surges of different duration are caused to exist which would produce a differential pressure above a predetermined limit. The bypass valve then opens, but the attendant has no knowledge of this. This device incorporates a signalling device in one bypass valve so that when the valve opens, corrective action may be taken to prevent damage to the system which may be caused by the bypassed contaminated fluid. With the exception of certain devices recently produced by applicants assignee, applicants do not know of any prior art devices which solve this problem.

SUMMARY OF THE INVENTION Our invention provides a device which is connected on one side to a high pressure side of a fluid or hydraulic or lubricating system and on the other side to the low pressure side of such system, which functions to give an indication whenever the pressure differential between the high pressure side and the low pressure side exceeds a predetermined limit and which also functions to bypass fluid from the high pressure side to the low pressure side in order to relieve high pressure when such pressure differential occurs, and signal when the bypass valve is open.

It is an object of our invention to provide a pressure indicator and pressure relief device in which a movable pressure responsive means subjected to high pressure and low pressure on opposite sides, functions to indicate the existence of such high pressure immediately upon the movable pressure responsive means moving in response to an increase in differential pressure.

It is an object of our invention to provide such a device in which when the predetermined pressure differential has been exceeded, and which is so constructed that the movement of the pressure responsive means is accelerated in order to promptly open a bypass passage so that higher pressure differentials will not be reached and so that the parts of the system will promptly be protected from possible damage.

It is an object of our invention to provide a device of the character described which includes a stepped cylinder and piston arrangement whereby when high pressure moves the piston from a seat, areas of the piston exposed to high pressure are increased so that the force available to open a bypass passage is increased in order to provide prompt and immediate bypassing.

It is a still further object of our invention to provide an arrangement of the character referred to in the preceding paragraph in which the piston is actuated upon by a biasing spring and in which immediately upon cracking the valve a means is operated to relieve the piston of the force of this spring, thus, upon cracking of the valve, increasing the force available to move the piston into bypassing position.

It is an object of our invention to provide an indicating and bypass pressure relief device in which the piston, when the valve is cracked, moves into an intermediate position whereby high pressure fluid is employed to operate the indicator means which indicates the increase in differential pressure, this indicator means being actuated before the piston moves into full bypassing position.

It is an object of our invention to provide an arrangement of the type referred to in which the pressure responsive piston, which upon movement opens the bypass, carries an indicator actuating piston and in which, upon initial movement of the pressure responsive piston, high pressure fluid is supplied in order to immediately operate the indicator actuating piston.

Other objects and advantages of our invention will be made evident in the course of the following detailed description of our invention.

BRIEF DESCRIPTION OF DRAWINGS Referring to the drawings:

FIG. 1 is a diagrammatic view illustrating a portion of a system including the features of our invention;

FIG. 2 is a longitudinal sectional view through a pressure indicator and bypass pressure relief device incorporating the features of our invention, this figure illustrating the position of the parts in a normal non-indicating non-bypassing position;

FIG. 3 is a sectional view taken on the line 33 of FIG. 2;

FIG. 4 is a view similar to FIG. 2 but showing the position of the parts promptly after a valve has been cracked and with the parts in a position to permit high pressure fluid to operate the indicator actuating means of our invention;

FIG. 5 is a view similar to FIG. 2 but showing the position of the parts in bypass pressure relief position; and

FIG. 6 is a sectional view taken on the line 6-6 of FIG. 3 showing the manner in which the valve seat element of our invention is seated against a shoulder in the cylinder.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1 the numeral 11 represents a conduit in the high pressure side of a fluid system and the numeral 12 represents a conduit in the low pressure side. There is a filter 14 which is representative of a fluid receiving device positioned between the high pressure and low pressure side of the system. This filtering device in the system illustrated performs the function of filtering the fluid passing through the system and removing any foreign bodies from it. In the course of the operation of the system the filter becomes spent and will gradually build up a back pressure so that the differential between the high pressure side and the low pressure side will be increased.

The pressure indicator and bypass relief device of our invention is indicated by the numeral 15 and is connected to the high pressure side of the system by suitable piping or conduit 16 and to the low pressure side by piping or conduit 17. Thus, it will be seen that the device 15 is in parallel with the filter l4 and when the bypass is open will permit fluid to bypass this filter.

Referring now to FIGS. 2 to 6, the details of construction of our invention and its operation will be described.

The body 20 is supported by a suitable housing 21 which is connected to the conduit 16 at 22 and to the conduit 17 at 23. Suitable seals 24 and 25 are provided to form a leak-proof space 26 in the housing 21. The body 20 has a dividing wall 27 which divides the body into a pressure responsive means chamber or piston chamber 28 and an indicator element chamber 29. The cylindrical wall 30 forming the cylinder 28 has an upper bleed 31 and a lower bypass passage or passages 33 which, when the parts are in bypassing position, provide a passage which connects the high pressure side of the system with the low pressure side of the system. The bypass passages 33 are pressure-drop ports whereby the pressure within the lower part of the chamber may be maintained above the pressure in the low pressure side of the system. Pressed against a shoulder 32, shown clearly in the fragmentary view, FIG. 6, is a valve seat element 37, which provides an annular knife edge valve seat, as indicated at 38. The seat element 37 is secured in place by a retaining ring 39. The diameter of the cylinder or chamber is indicated a 0. However, this diameter is reduced to a diameter marked b by reason of the fact that the seat element 37 provides a cylinder section 40, which is of reduced diameter. The seat element 37 and ring 39 provide a central passage 41 which comprises a high pressure passage to the annular seat 38, this passage 41 having the diameter marked a.

Within the chamber or cylinder is a differential pressure responsive means in the form of a piston, generally designated by the numeral 42, which has a skirt 43 which is of substantially the diameter of the cylinder.

The piston is stepped at 44 and reduced to a cylindrical portion 45, which is substantially the diameter b." However, there is sufiicient clearance between 45 and 40 to provide a leakage path which functions as will be described. The piston 42 has a head 46 having a conical valve face 47 which, when in engagement with the seat edge 38, as shown in FIG. 1, forms a pressure pocket 48. The head 45 has a plurality of communicating passages 49 which communicate the pressure pocket 48 with a space 50 within the piston member.

The piston has an insert member 51 having a head 52 which seats against the head 46 in a substantially fluidtight relationship, as indicated at 53. The head 52 provides a shoulder engageable by a biasing spring 54, which exerts a pressure tending to hold the piston against the seat 38.

The insert member has a cylinder 56 having a bore 57 connected at its lower end to the space 50 by a passage 58. Positioned within the bore 57 is indicator actuating means in the form of a piston 59 having a shoulder 60 which is held against the upper end of the cylinder 56 by means of a compression spring 61. When the parts are in the position as shown in FIG. 2 the force of the spring 61 is applied to the piston 42 by reason of the fact that the flange 60 is in engagement with the cylinder 56. The upper end of the piston 59 carries a magnet 62 suitably secured in place, the magnet having N and S poles and positioned below the wall 27.

Our invention provides an indicator element generally designated by the numeral 70 which has body 71 supported within the chamber 29, the upper end of which chamber being closed by an iron cap 72, which is held in place by a crimped lip 73. Recess 74 of the body 71 carries a magnet 75. It will be noted that the magnets 62 and 75 have like poles on adjacent sides so that when the magnets are brought into adjacency there is a repelling action. The indicator element 70 has an indicator portion 76 which may project through a central cylindrical opening in the iron plate 72 when it is in actuated position, as shown in FIGS. 4 and 5. A compression spring 78 normally holds the indicator element 70 in its retracted position, as shown in FIG. 2, with the north pole of the magnet 75 being attracted to the iron plate 80.

As previously pointed out, the parts as shown in FIG. 2, are in the positions that they occupy when there are no unusual pressure differential conditions existing between the high pressure side and the low pressure side of the system. At this time the pressure in the high pressure side pressing against the areaa"a of the piston 42 exerts a force in a direction tending to move the valve head 46 from its seat 38. At this time, however, there is low pressure bearing against the low pressure side of the piston 43 and, in addition, there are the biasing forces of the springs 54 and 61 which are adequate to hold the piston 42 in seated position. The strength of the biasing springs 54 and 61 in combination with the low pressure fluid pressure will hold the piston seated during all normal and usual operations in the system.

Should there be any leakage past the valve seat 38 there is sufiicient clearance around the cylindrical portion 45 so that a bleed is provided which prevents fluid from building up a pressure against the enlarged end of the upper cylindrical portion of the piston 42 and thus inadvertently or improperly unseat the indicating piston. At this time, of course, there having been no unusually high pressure having occurred in the high pressure side of the system, the indicator element 70 is being held in non-indicating position by the force of the spring 78 and the magnetic pull on the iron plate 80 as previously explained.

Whenever there is an increase in differential pressure of a value sufficient to overcome the forces tending to hold the piston 42 in seated position, this piston will move away from its seat into an initial cracked position. This may occur by a pressure surge in the system or by the filter 14 or other element in the system building up a back pressure such, for example, as would occur if the filter 14 becomes clogged over a period of use.

When this increase in pressure occurs the piston will move into the cracked position as shown in FIG. 4. This will provide communication through a very small annular space to the pressure pocket 48 and at this time fluid will flow through the leakage path between the surfaces 40 and 45, as previously explained, but a major portion of the fluid will pass through the openings 49, the space 50, passage 58, and into the lower end of the cylinder 57, thus moving the piston 59 upwardly against the action of the spring 61 and into the position as shown in FIG. 4. At this time the repelling forces of the magnets will move the indicator into indicating position, as shown in FIG. 4. At the instant the shoulder 60 moves away from the end of the cylinder 56 the biasing force of the spring 61 is removed from the piston and the piston 42 is now held down only by the low pressure fluid and the spring 54.

I At this time in the operation of the structure the area of the piston 42, which is exposed to high pressure, has been increased from area a" to area b and, in addition to this, the force of the spring 61 has also been removed from the piston. This sudden increase in exposure of piston area to high pressure in combination with the reduction of the force of the spring 61 causes the piston 42 to rapidly move from the position shown in FIG. 4 into the position shown in FIG. 5.

In change of position from FIG. 4 to FIG. 5 the only parts which have moved are the piston 42, which is moved away from its seat 38 a distance sufficiently to fully open the bypass passages 33, and the spring 54 has been further compressed with the result that the forces on opposite sides of the piston 42 are balanced with the piston positioned as shown in FIG. 5.

The bypass ports 33 are of such a size that a pressure drop will occur across them in order to maintain in the space at the high pressure end of the piston 42, a pressure sufficiently high to keep the piston balanced in the bypassing position during the time that high pressure continues in the high pressure conduit 11. When the piston 43 moves from the position shown in FIG. 4 to the position shown in FIG. 5 the indicator actuating piston 59 will remain in a fixed position and a telescopic action between the two pistons will occur at this time.

The moving of the piston 42 to fully open position exposes the full diameter 0 of the piston 42 to high pressure thus allowing a relatively lower differential pressure as compared to the cracking pressure, to hold the piston in full bypassing position. To close the bypass valve the differential pressure must reduce in order to allow the piston 42 to move toward its seat and to gradually close the bypass passages or ports 33. As the piston 42 moves in this direction the piston head 46 will move into the counterbore 40 resulting in a sudden reduction of area exposed to fluid pressure, the area being reduced from the area c to the area b," thus returning the parts to a relationship which may approach that shown in FIG. 4. Thus, the reseating pressure which is a function of the ratio of a" to b can be designed to close the valve to cracking position without excessive penalty in full flow pressure drop.

If the pressure in the high pressure side of the system should drop to normal limits, the parts will then return to the position shown in FIG. 2 with the exception that the indicator will be in an extended position so that an attendant will know that there has been an increase in differential pressure and that his investigation of the facts which cause the operation of the indicator should be investigated.

We claim:

1. A pressure indicator and bypass and pressure relief device, the combination including:

a. a body having a chamber which has a high pressure inlet and a low pressure outlet with a seat adjacent to said high pressure inlet and with a pressure pocket located adjacent to and downstream of said seat;

b. a piston movable in said chamber and exposed on one side to high pressure and on the other side to low pressure, said piston having a valve means adapted to engage said valve seat; and

itial movement of said piston, said indicator means comprising an indicator element movable within a second chamber in said body, said second chamber having a wall to urge said piston in a direction away from said indicator element. 4. A pressure indicator and bypass pressure relief device,

the combination including:

structurally separating it from the first chamber in said a. a first chamber adapted to be connected to a high presbody, indicator operating means carried by said piston sure zone and a low pressure zone with a seat positioned and movable to actuate said indicator means, means conat the high pressure end of said chamber; nected between said pressure pocket and said indicator ba second chamber adjacent the low pressure end of said operating means whereby upon initial movement of said first chamber, said second chamber having a dividing wall piston away from said fluid under pressure may flow to 1 sep ing Said first and Second Chamber; said indicator operating means to operate same, and said a first Piston movable in Said first Chamber. Said pi indicator element being adapted to move within said being exposed on one Side to high P and on the second chamber in a direction toward and away from the other Side 10 10W Pressure, Said Piston having a valve fi first chamber due to cooperative interaction with said adapted to g g Said Seat; pressure a t t d i di operating means d. an indicator element movable within said second 2. A combination as defined in claim 1 in which said indicachamber Comprising:

{of element comprises; 1. an indicator element body;

a. an indicator element body movable within the second a magnet having a non-h and Somh P carried y Said chamber; indicator element body; and

a magnet having north and south poles carried by said 3. means within said second chamber for biasing said inbody; and dicator element body toward said first chamber;

c. a spring supported within the second chamber and p j qp q mdlcator p a m means camed y adapted to urge said indicator element body toward the sa1d first P Q i sa1d means comPnsmgl fi t chamben l. a second piston movable relative to said first piston in a 3. A combination as defined in claim 2 in which said indicadirection toward and y from Said indicate)" element tor operating means comprises: 2. a magnet having a north and south pole carried by said a. an indicator operating piston supported within the first condemn, f magnet P to urge chamber in Said body said piston being adapted to move separation of said second piston and said indicator elewithin the first chamber in a direction toward and away and from Saidindicator element; 3. means for urging said second piston toward the low b. a magnet having north and south poles carried by said in- Pressure end ofsald first chafnbFri and dicator operating piston, said magnet being arranged so f means h sa1d P f has moved a Short that as said piston moves toward said indicator element dfstanfze Its seat m fombmauon l f for said magnet presents a like pole to the proximate pole of f pressure mud to operate sa1d mdlcato' said magnet of said indicator element; and operatmg means c. a spring supported within the first chamber and adapted 

1. A pressure indicator and bypass and pressure relief device, the combination including: a. a body having a chamber which has a high pressure inlet and a low pressure outlet with a seat adjacent to said high pressure inlet and with a pressure pocket located adjacent to and downstream of said seat; b. a piston movable in said chamber and exposed on one side to high pressure and on the other side to low pressure, said piston having a valve means adapted to engage said valve seat; and c. indicator means movable into a position to indicate an initial movement of said piston, said indicator means comprising an indicator element movable within a second chamber in said body, said second chamber having a wall structurally separating it from the first chamber in said body, indicator operating means carried by said piston and movable to actuate said indicator means, means connected between said pressure pocket and said indicator operating means whereby upon initial movement of said piston away from said fluid under pressure may flow to said indicator operating means to operate same, and said indicator element being adapted to move within said second chamber in a direction toward and away from the first chamber due to cooperative interaction with said pressure actuated indicator operating means.
 2. A combination as defined in claim 1 in which said indicator element comprises: a. an indicator element body movable within the second chamber; b. a magnet having north and south poles carried by said body; and c. a spring supported within the second chamber and adapted to urge said indicator element body toward the first chamber.
 2. a magnet having a north and south pole carried by said indicator element body; and
 2. a magnet having a north and south pole carried by said second piston, said magnet being oriented so as to urge separation of said second piston and said indicator element, and
 3. means for urging said second piston toward the low pressure end of said first chamber; and f. bleed means operable when said piston has moved a short distance from its seat in combination with means for directing high pressure fluid to operate said indicator operating means.
 3. means within said second chamber for biasing said indicator element body toward said first chamber; e. pressure operated indicator operating means carried by said first piston, said means comprising:
 3. A combination as defined in claim 2 in which said indicator operating means comprises: a. an indicator operating piston supported within the first chamber in said body, said piston being adapted to move within the first chamber in a direction toward and away from said indicator element; b. a magnet having north and south poles carried by said indicator operating piston, said magnet being arranged so that as said piston moves toward said indicator element said magnet presents a like pole to the proximate pole of said magnet of said indicator element; and c. a spring supported within the first chamber and adapted to urge said piston in a direction away from said indicator element.
 4. A pressure indicator and bypass pressure relief device, the combination including: a. a first chamber adapted to be connected to a high pressure zone and a low pressure zone with a seat positioned at the high pressure end of said chamber; b. a second chamber adjacent the low pressure end of said first chamber, said second chamber having a dividing wall separating said first and second chamber; c. a first piston movable in said first chamber, said piston being exposed on one side to high pressure and on the other side to low pressure, said piston having a valve face adapted to engage said seat; d. an indicator element movable within said second chamber comprising: 